Computing devices are using increasing percentages of total generated electric power. Power consumption management of computing devices provides an opportunity for making more ideal use of resources and for reducing the carbon footprint of computing devices. Beyond fiscal and environmental benefits, power management can also prolong device operation when a portable device is constrained to use limited battery resources. By employing careful management of power consumption, mobile computing devices may perform additional work by leveraging power conserved from each charge of a battery that may have otherwise been needlessly used by powering underutilized resources, allowing longer usage as well as for enhanced experiences such as usage for enhanced displays.
Traditional power conservation techniques often rely on user adjustments to power usage by allowing users to specify and choose relatively static policies for allocating power to devices. For example, a user may adjust a power setting to control processor speed, dim/brighten a display, or enable/disable a device. In addition, processors often include power management features that enable the processor to operate at various power consumption modes or states, such as an active state, a low power state, an idle state, or a sleep state. Some policies allow for the changing of resource usage via measures of sensed idle times, such as dimming a display when user activity is not observed for some specified amount of time.
On a finer grain, processors often include logic to adjust the power consumption mode based on real-time processing demand and policies can be invoked by manufacturers and users to control the tradeoffs between the performance and efficiency of a processor and its power consumption.
Although most components of a computing device use power during operation, the processor uses a disproportionate share of the computing device's power. Many computing devices include multiple processors and/or processors with multiple cores, which further provide an incentive to reduce power consumption of the processors.